DE2543748C2 - Sequential system for the transmission of color television signals - Google Patents

Abstract

The invention relates to a device for removing gases from a closed container at high voltage potential, which is arranged within a pressure tank, the space between the pressure tank and the container being filled with a gaseous insulating material that is higher than atmospheric pressure. With such devices, for example for generating and accelerating hydrogen agglomerate ions, a number of technical difficulties arise, in particular that complex devices for increasing the gas pressure and for removing the gas are required, which provide access to the interior of the high voltage - Make the electrode much more difficult during necessary maintenance work and impair the operational safety of the system. The invention makes it possible to discharge gases occurring at low pressure during operation and still maintain operational reliability even at high voltages and ensure simple maintenance through easy access to the interior of the high-voltage electrode, which only requires brief interruptions in operation. It is characterized in that the container is connected to the outside of the pressure tank by a pipe which runs vertically upwards and consists of an insulator. The container is filled with an insulating liquid. On the container, one or more outlet devices allow the entry of gases from the container in ... U.S.W.

Description

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The invention relates to a system of the type mentioned in the preamble of claim 1.

From DE-OS 22 37 317 is already a line sequential Color television transmission system known in which luminance information alternately during a line time and color information and the low frequency information during a subsequent line time Part of the luminance information is transmitted from a signal transmitter to a signal receiver. Here there is no vertical resolution reduction in the luminance signal, because during each line time at least the low-frequency part of the luminance signal is transmitted.

In the digital transmission of color television signals A distinction is made between separate and closed coding. With the latter it will complete color television signal sampled, encoded and transmitted. A message reduction of the full color television signal cannot be performed to a sufficient extent.

With separate coding, the luminance component is separated from the color component of the color television signal, both parts coded and mostly in time division multiplex

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transmit a channel. With this method, a message reduction is easier and a sufficient picture quality appears with known methods with a channel capacity of about 40 Mbit. To split the color television signal into a luminance and a color component
A comb filter is particularly advantageously used. The resulting color difference signals could then be transmitted simultaneously, which, however, requires a channel capacity of around 20 Mbit. The great need for channel capacity for the Farbarisigna is too high in view of a channel capacity of 34 Mbit available for the full color television signal.

From the magazine NTZ, 1972, issue 2, p. 102, 103 isi Although already known in the coding and transmission of the color television signal, to reduce the Data flow in moving image templates to be transmitted only every 2 fields. However, this leads to a zi strong reduction in the resolution of the entire image information.

The object of the present invention is therefore that which is necessary for the transmission of the color information Reduce channel capacity.

The solution to this problem is characterized by the features of claim 1.

A further development of the invention according to claim 2 enables a continuous flow of data with relatively little storage effort.

The system according to the invention can be implemented in a two-channel design for the transmission of two color difference signals can be used or in a simple version for the transmission of the color information the patent application P 25 04 460. (Line by line alternating the sum and the difference of the color difference signals.)

On the receiving side there is a color field memory, which replaces the non-transmitted fields with the repetition of the previous fields. The frame rate (decisive for the motion resolution) is then (as in a movie) 25 frames / s. Due to the one-time repetition of the images (from the memories), the grid change frequency also remains of 50 Hz (decisive for the flicker impression). This is accepted Process a reduced vertical resolution, since the color image only consists of 312.5 transmitted lines consists. Since the chrominance signal in the horizontal direction is already around the Has a factor of 4 lower resolution, this means only one step to align horizontal and vertical color resolution.

The invention is explained in more detail with reference to the figures, which show

F i g. 1 schematically shows an exemplary embodiment according to the invention and

F i g. 2 an overview of the occupancy status of the memory.

The F-BAS signal supplied at A is split up in a circuit B known per se into a luminance signal and a chrominance signal. The transmission of the luminance signal Y is not the subject of the present invention and is therefore not described in more detail. The chrominance signal C , which is still carrier-frequency after the separation, is demodulated in a demodulator D and then digitally encoded in the coder E , for example according to the DPCM method. If the procedure according to P 25 04 460 were used, they would be

Output signals of the coder £ alternating line by line (U - V) and (U + V). The switch F illustrates that color information is only forwarded during every other field. Otherwise, the memories C, H and / are only shown symbolically. The circuits available for writing in and reading out are known per se and, like the clock-correct control of the memory, do not need to be shown in this context.

The switch F as well as the other switches K and L are controlled with the vertical frequency and are for the sake of clarity in FIG. 1, although in the practical implementation of a system according to the invention, under certain circumstances, its function can be taken over by appropriate clocking of the memory.

The transmission of the individual color information is described in connection with FIG. 2 explained in more detail After the information has been read out from the memories H and / or the signals can be fed via a decoder M and a modulator N to an adder circuit in order to achieve a complete color television signal.

In Fig. 2 the content of the memories G, H and / and the combination of the signals taken from the memories H and / is shown schematically for times successive by 20 ms.

In order to obtain an even flow of data from the transmitter to the receiver, it makes sense to forward every 1st, 3rd, 5th, ... ^ ... to store image points in a buffer memory G at the transmitting device (memory size: half a field) and to transmit these image points to the receiver during the time of the color half-image not being transmitted. Here, the image points 1st, 3rd, 5th are initially written into the memory H during Γι. The pixels 2nd, 4th, 6th, which are transmitted during Ti , are also written into the memory. At the same time these pixels are but the first with the pixels, 3, 5, reassembled into a n full field and the trains hearing brightness field added The color image field is now fully stored in two half field memories and, during T ₃ from the memory H and / to be repeated out. The repeated color half-image is also added to the next brightness half-image. Simultaneously with this image repetition, however, the image points U 3rd, 5th - in FIG. 2 marked with a, c, e - the next color field to be transmitted can already be stored in the first half field memory H.

The color image is shifted by see compared to the brightness image. Therefore it can be very fast Movements lead to a slight colored tracing in the picture. This can be avoided in that a field memory may be arranged in the transmission path for the brightness component. This only serves to delay the brightness signal by one field (V50 see). This means that color and brightness are in their duration largely (sufficiently) aligned.

This memory as well as the memory for the color information can be used as an error compensator to serve. A color television signal digitized using DPCM places high demands on the quality of the Transmission channel. A single bit error per field can result in the spread of errors Interfere strongly with the field. Error protection is therefore always added to such signals. The most popular Error protection methods are able to handle a large number of to correct the occurring transmission errors. The residual errors usually lead to at least one Error message. This error message can be used to prevent the registered mail for a given To prevent time, so that the prerequisite error-free signal remains in the memory. These predetermined time depends on the type of coding and can be, for example, a line or field period.

For this purpose 2 sheets of drawings

Claims (4)

Patent claims: 1. Most sequential for the transmission of color television signals in successive time intervals, the luminance information according to a known method continuously and the Color information is only transmitted from every second time interval, thereby marked n e t that for digital transmission of the color television signal the color information is only transmitted from every other field. 2. System according to claim 1, characterized in that a memory (G) is provided in a transmitting device, in which the color information of every second pixel of a field are written, while the color information of the intervening pixels of the field are transmitted over a transmission path and in one first memory (H) are written in a receiving device so that in the subsequent field period the color information written in the memory (G) in the transmitting device is transmitted, written in a second memory (I) in the receiving device and simultaneously with that in the first memory (H) color information present in the receiving device is combined and read out in two successive time intervals and added to the luminance information. 3. System according to claim 2, characterized in that a further memory is preferably in the Receiving device is provided for the luminance information. 4. System according to claim 2 or 3, characterized in that an error detection circuit is provided and that in the case of faulty signals, the writing of the transmitted signals into the memory of the receiving device for a predetermined time - preferably one line period - is prevented.